Google API Class for online PR checking (asp .net)


using System;
using System.Data;
using System.Configuration;
using System.Linq;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Xml.Linq;
using System.IO;
using System.Net;
using System.Text;
using System.Text.RegularExpressions;

/// <summary>
/// Summary description for Get_PR1
/// </summary>
public class Get_PR1
{
    /// <summary>
    /// Returns the PageRank of the given URL. Return values are 0 through 10 or
    /// -1 (N/A), which indicates there was an error or the URL is not in the
    /// Google index.
    /// </summary>
    /// <param name="url">URL to test</param>
    /// <returns></returns>
    public static int GetPageRank(string url)
    {
        int rank = -1;

        try
        {
            // Form complete URL
            url = String.Format("http://toolbarqueries.google.com/tbr" +
                "?client=navclient-auto&features=Rank&ch={0}&q=info:{1}",
                ComputeHash(url), UrlEncode(url));

            // Download page
            HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
            StreamReader stream = new StreamReader(request.GetResponse().GetResponseStream());
            string response = stream.ReadToEnd();

            // Parse page rank value
            string[] arr = response.Split(':');
            if (arr.Length == 3)
                rank = int.Parse(arr[2]);
        }
        catch (Exception)
        {
            // Do nothing but return -1;
        }
        return rank;
    }

    /// <summary>
    /// URL-encodes the given URL. Handy when HttpUtility is not available
    /// </summary>
    /// <param name="url">URL to encode</param>
    /// <returns></returns>
    private static string UrlEncode(string url)
    {
        StringBuilder builder = new StringBuilder();

        foreach (char c in url)
        {
            if ((c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z') || (c >= '0' && c <= '9'))
                builder.Append(c);
            else if (c == ' ')
                builder.Append('+');
            else if ("()*-_.!".IndexOf(c) >= 0)
                builder.Append(c);
            else
                builder.AppendFormat("%{0:X2}", (byte)c);
        }
        return builder.ToString();
    }

    /// <summary>
    /// Computes a hash value required by Google
    /// </summary>
    private static string ComputeHash(string url)
    {
        UInt32 a, b;
        UInt32 c = 0xE6359A60;
        int k = 0;
        int len;

        // Modify URL
        url = string.Format("info:{0}", url);

        a = b = 0x9E3779B9;
        len = url.Length;

        while (len >= 12)
        {
            a += (UInt32)(url[k + 0] + (url[k + 1] << 8) + (url[k + 2] << 16) + (url[k + 3] << 24));
            b += (UInt32)(url[k + 4] + (url[k + 5] << 8) + (url[k + 6] << 16) + (url[k + 7] << 24));
            c += (UInt32)(url[k + 8] + (url[k + 9] << 8) + (url[k + 10] << 16) + (url[k + 11] << 24));
            Mix(ref a, ref b, ref c);
            k += 12;
            len -= 12;
        }

        c += (UInt32)url.Length;
        switch (len)
        {
            case 11:
                c += (UInt32)(url[k + 10] << 24);
                goto case 10;
            case 10:
                c += (UInt32)(url[k + 9] << 16);
                goto case 9;
            case 9:
                c += (UInt32)(url[k + 8] << 8);
                goto case 8;
            case 8:
                b += (UInt32)(url[k + 7] << 24);
                goto case 7;
            case 7:
                b += (UInt32)(url[k + 6] << 16);
                goto case 6;
            case 6:
                b += (UInt32)(url[k + 5] << 8);
                goto case 5;
            case 5:
                b += (UInt32)(url[k + 4]);
                goto case 4;
            case 4:
                a += (UInt32)(url[k + 3] << 24);
                goto case 3;
            case 3:
                a += (UInt32)(url[k + 2] << 16);
                goto case 2;
            case 2:
                a += (UInt32)(url[k + 1] << 8);
                goto case 1;
            case 1:
                a += (UInt32)(url[k + 0]);
                break;
            default:
                break;
        }
        Mix(ref a, ref b, ref c);
        return string.Format("6{0}", c);
    }

    /// <summary>
    /// ComputeHash() helper method
    /// </summary>
    private static void Mix(ref UInt32 a, ref UInt32 b, ref UInt32 c)
    {
        a -= b; a -= c; a ^= c >> 13;
        b -= c; b -= a; b ^= a << 8;
        c -= a; c -= b; c ^= b >> 13;
        a -= b; a -= c; a ^= c >> 12;
        b -= c; b -= a; b ^= a << 16;
        c -= a; c -= b; c ^= b >> 5;
        a -= b; a -= c; a ^= c >> 3;
        b -= c; b -= a; b ^= a << 10;
        c -= a; c -= b; c ^= b >> 15;
    }
}


=========

Server side Code..for the function call:

int PR=Get_PR1.GetPageRank(url);   // output will be the PR value of the URL
 lbl_pr.Text = Convert.ToString(PR);    // publish PR on level.........